Treatment of ocular surface disorders requires medical and surgical intervention, both acutely and in the long term. Regardless of the underlying causes involved, the common goals of management include controlling inflammation and promoting ocular surface healing with maximal visual rehabilitation. Various medical therapies have been used to achieve these objectives.
Amniotic membrane (AM) graft has been used in ophthalmology for several indications because of its beneficial effects. Previous studies revealed that early intervention with amniotic membrane transplantation (AMT) results in marked reduction of inflammation, rapid restoration of the ocular surface, and improved visual acuities while preventing cicatricial complications (Dua 2004). However, surgically performed AMT renders a relatively high cost and potentially unnecessary surgical trauma in such compromised eyes. Furthermore, the membrane patch usually dissolves within several days so that multiple sessions of AMT may be required. Recently, a self-retaining AM mounted on a double ring system (Prokera, Biotissue Inc., Miami Fl.) has been effectively used to promote healing and reduce corneal scarring in acute chemical burn and bacterial keratitis (Sheha 2009), however, patients experienced ocular discomfort from the ring and incomplete healing due to improper centration of the device.
Recent studies have shown that topical amniotic membrane extract (AME) has comparable effect to AMT in promoting epithelialization, decreasing inflammation, and suppressing corneal neovascularization. However amniotic membrane extract lacks the physical characteristics of a bandage and as such it cannot be used as a patch graft (Sheha 2010).
In summary, amniotic membrane dissolves too rapidly for prolonged use and it requires application by surgical intervention. Amniotic membrane retained by a ring does not require surgery—but it is obtrusive, not well tolerated and as a result it suffers from sub-optimal therapeutic outcomes. Amniotic membrane extract—though it shares the healing qualities of intact amniotic membrane—it does not have the physical characteristics of a patch.
There is, therefore, a need for a delivery device that is a self-retaining patch that is applied using non-surgical means, is well tolerated by patients, lasts for an extended period of time and does not require a mechanical ring structure for maintaining the patch in position.